a) Average velocity for her run north: 2.68 m/s north
b) The average velocity for the whole trip is zero
c) The average speed for the whole trip is 1.95 m/s
Explanation:
a)
In this part of the problem we only want to consider the part when Micha is running north.
The average velocity is given by:
where
d is the displacement (a vector connecting the initial position to the final position of motion)
t is the time
For the part running north, we have
north is the displacement
is the time interval
Substituting,
north (we have to specify also the direction, since velocity is a vector)
b)
As we said, average velocity is given by
where
d is the displacement
t is the time
If we consider the whole trip, however, the displacement is zero:
d = 0
Because Micha returns home, so the initial position corresponds to the final position of motion. Therefore, the average velocity is also zero:
v = 0
c)
The average speed is given by
where
d is the distance covered (the total length of the path, regardless of the direction)
t is the time interval
Since MIcha ran 2 miles north and then 2 miles back, the total distance is
And the time taken is
So, the average speed is
And since speed is a scalar, there is no need to specify a direction.
Learn more about speed and velocity:
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